Thread-controlling device



- 1,452,33 A. F. FIFIELD THREAD CONTROLLING DEVICE Apr. 17, 1923.

Filed Sent. 1920 iiiiair'm 7 1 WITNESSES: f INVENTOR Patented short. W, i923.

ALBERT F. FIFIELD, OF NEWARK,

JERSEY.

ILEW' JERSEY, ASSIGNOR TG THE SINGER IIIANU- THBEAD-CONTROLLING DEVICE.

Application filed To all whom t may concern Be it known that l. iLnnn'r l nirnznin a citizen of the United States, residing at lflewarln in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Thread-Controlling Devices, of Which the following is specification, reference being had therein to accompanying drawings.

This invention relates to a thread-con trolling device for sewing machines, its object beii to prevent breakage of the thread and con prises a yieldable threadguide acting as a safety device to prevent breakage of the thread should an abnormal pull be imparted the eto.

lt consi preferably of a yieldable guide wh ch may be located between the tension device and the take-up and so arranged that undernoi'mal operation it acts merely as a statioi 1v guide, but should an abnormal pull be placed on the thread the guide will yield up enough thread to prevent abnormal tension and so prevent breakingot the tiread.

Reference is made to the accompanying d swings in which E 1 shows a portion of the overhanging bracket arm or a sewing" machine with my device applied thereto. Fig. is a sectional elevation of my yieldable thread'guide. Figs. 3 and 4 are sections on the lines 33 and l d, respectively, of Fig. l and F 5 is an eleva tion o1 the device illustrating its action when an abnormal strain is imparted to the thread.

Reference numeral 1 indicates the overhanging; bracket-arm of the machine in the head of WlllCli is mounted for vertical reciprocation the needle-ha :2 provided at its upper end with a needle-thread takeup 3. Secured upon the upper portion of the bracket 1 by a suitable support 4t is the constant tension device 5 and also pivoted to this bracket or support 4- is the presserbar lilting lever 6.

Between the constant tension device 5 and the needle-thread take-up 3 is secured a yieldable threadguide Which comprises a post 7 adjust-ably secured in a socket in the bracketarm 1 by means of a set-screw 8, said post beingprovided with a fiat side 8 for the end or" the S6iSC1Q-W. The post is provided with a transverse slot 9 extending therethrough, and secured upon the post by 1320. Serial No. 407,623.

means of a pin 10 is'a collar 11 which is cut away at 12 in alignment with the transverse slot 9 to provide on opposite sides of the post upwardly extending portions 13. Also mounted upon the post and adapted to freely slide thereon is the collar let provided with a reduced portion embraced by the coil spring 15. The upper end of the spring 15 abuts against a collar 16 adjustably mounted upon the upper end of the post 7 by means of set screiv 17 the post being also provided at this end with a flat portion 17 forminga seat for the end of this screw.

A thread 5' is led from the supply through a guide 17 to the constant tension device i then under the lower end the collar 14: hroug h the slot 9 and at substantially right angles over the take-up 3 through the guide 8 to the needle. it Will be noted that the raised portions 13 of the collar ll serve to space the end of the collar 1% from the lower end of the slot 9 allowing free passage of the thread. l'hroughthe slot under the collar ll. The spring 15 is normally under sufficient tension that it will no t yield during; normal stitchingoperation being of suilicient strengthto allow the take-up 3 to pull thread through the tension 5 Without yielding and thus under normal operation acts merely as a stationary guide. if, however, the strain on the thread should become abnomnal the spring; 15 Will yield allowing the collar l l-v to rise, as shown in Fig. 5, giving up sufiicient thread to compensate for the increased tension thereon and thus preventing lueaking' thereof.

It will be seen that my device forms a safety attachment for the thread oi? simple construction, inexpensive to manufacture and occupies very little space upon the head of the machine and effectively prevents breakage of the thread should it be subjected to an undue pull.

Having thus set forth the nature of the invention, What I claim herein is 1. In aseving machine having stitchforming mechanism including a need e, a

take-up, and a yieldtension device, a thread able guide for the thread stronger than the tension device and located between the tension device and the needle, whereby said guide Will be unyielding duringnormal operation of the machine but will yield and give up thread shou d an abnormal pull be applied to the thread.

portions,the thread being led from the tension through the slot between the two collars I andthen at substantially right angles to the take-up.

3. In a sewing machine having stitchforming mechanism, a constant tension device, a thread take-up, and a yieldable guide for the thread between the tension device and the needle'comprisin a post provided with a transverse slot, a collar secured to the post and having extensions on opposite sides of the lot, a second collar freely slidable on. the post and adapted to rest on the free ends of the extensions on the first collar, a third adjustable collar on said post, and a coil spring between the second and third colla'rs of suiiicient tension to prevent yielding under the normal pull applied to the thread.

t. A yielding threadsguide for sewing machines comprising a post provided with a transverse slot extending therethrough, a stop on the post intermediate the ends of the slot, a collar freely slidable on the post,

a spring mounted on the post and tendingto urge the collar against said stop, and means for adjusting the tension of thespring.

5. A sewing machine having stitch-forming mechanism including a reciprocating needle-bar carrying a needle, a tension device, a take-up thread-guide carried by the needle-bar, and a thread-guide intermediate the needle-bar and the tension device, said last-mentioned thread-guide comprising pressure exerting and pressure sustaining members, at least one of which is cut away to avoid nipping the thread'passing intermediate said members, the pressure exerting member being stronger than the tension device. y

6. In a sewing machine having a bracketarm, thecombination with a reciprocating needle-bar having a take-up thread-guide, and a tension device, of a cooperative threadguide comprising a slotted post mounted on the bracketarm' of the machine to engage the thread between the needle-bar and tension device, a coil spring surrounding the post and at its lower end adapted to exert a downward pressure of predetermined intensity, and means independent ofthe thread for sustaining said pressure,vwhereby the thread will not be nipped, said spring being adapted to yield to the thread only under an abnormal pull.

In testimony whereof, I have signed myname to this specification F. FIFIELD. 

